Your Urine

Your first trip to the toilet in the morning can detect a lot more than pregnancy or a urinary tract infection. More than 70 markers in your urine can determine how your entire body is functioning and are key to preventing degenerative diseases, unknown gluten intolerance, low antioxidant levels that make you vulnerable to oxidative stress and more, says Nancy Guberti, certified nutritionist and healthy lifestyle coach.
For instance, “accumulation of specific organic acids in urine often signals a metabolic inhibition or block,” Guberti says. The abnormality could mean that you’re vitamin deficient.
Your Weight

Unexplained weight gain and loss can also signal a health issue, says Dr. Julie Chen, an integrative physician and health expert. Don't ignore them. If you unexpectedly gain a lot of weight, this can signify hypothyroidism, adrenal disorders, fluid retention or pregnancy.
If you unexpectedly lose a lot of weight, this can signify cancer, hyperthyroidism, autoimmune diseases, chronic diseases and depression.
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Your Teeth

Dr. Lucy Slutsky, a general dentist based in West Orange, N.J., points out, “Oral hygiene and checkups are vital because dental problems can often be a sign of other health-related problems tied to the heart, lungs, digestive system or other parts of the body.”
Dental checkups can also give dentists the opportunity to check for early signs of oral cancer.
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Your Skin

You should be in the habit of checking your skin at least once a month to look for changing moles or non-healing lesions, says Dr. Tim Abou-Sayed, board-certified plastic surgeon. “Remember that the only ‘good tan’ is the one you are born with; when you get that tan from sunning yourself at the beach, you are actually damaging your skin with the sun’s radiation,” Abou-Sayed adds.
“A melanoma, which can be fatal, may begin as something so seemingly innocent as a slightly darkened mole, so a simple self-exam of the skin can alert you that you need to go to a dermatologist for a full screening.”
Dr. Glenn Kolansky, board-certified dermatologist in Red Bank, N.J., suggests you use a mirror for the back or hard-to-reach places, or have a significant other assist you. "It is also important to realize that a skin exam is only good on the date it is performed. Growths can change a day, a week or a month later," he says.
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Your Home

Don’t forget to also check your surroundings, which can indicate health issues and even save your life. “To live a healthier lifestyle, it is extremely important to maintain a ‘healthy home’ and be aware of toxins and other irritants that can exist in your living space and make you feel unhealthy,” says Caroline Blazovsky, national healthy home expert and certified mold remediator.
“If you notice headaches, congestion, respiratory irritation, asthma or allergies, you should have your home tested for mold, allergens and chemicals. Molds, for example, can produce spores, mycotoxins, and MVOCs (chemicals produced by mold), which can give you an array of symptoms and cause you to feel unwell.”
Blazovsky suggests monitoring such conditions every few years to every year to see if your home is within safe limits. You can even try a mold test kit of your own.